Re: [PATCH v4 03/12] IIO: hw_consumer: add devm_iio_hw_consumer_alloc

[Jonathan Cameron <jic23-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>]

On Thu, 9 Nov 2017 11:12:25 +0100
Arnaud Pouliquen <arnaud.pouliquen-qxv4g6HH51o@public.gmane.org> wrote:

> Add devm_iio_hw_consumer_alloc function that calls iio_hw_consumer_free
> when the device is unbound from the bus.
> 
> Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen-qxv4g6HH51o@public.gmane.org>
Hmm.. I normally don't like devm for what is a single use case in
a driver (for now) but I guess this is generic enough it will have
additional users reasonably soon.  Hence fine.

Jonathan
> ---
>  drivers/iio/buffer/industrialio-hw-consumer.c | 70 ++++++++++++++++++++++++++-
>  include/linux/iio/hw-consumer.h               |  2 +
>  2 files changed, 70 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/iio/buffer/industrialio-hw-consumer.c b/drivers/iio/buffer/industrialio-hw-consumer.c
> index 7d4d800..e980a79 100644
> --- a/drivers/iio/buffer/industrialio-hw-consumer.c
> +++ b/drivers/iio/buffer/industrialio-hw-consumer.c
> @@ -129,15 +129,81 @@ EXPORT_SYMBOL_GPL(iio_hw_consumer_alloc);
>   */
>  void iio_hw_consumer_free(struct iio_hw_consumer *hwc)
>  {
> -	struct hw_consumer_buffer *buf;
> +	struct hw_consumer_buffer *buf, *n;
>  
>  	iio_channel_release_all(hwc->channels);
> -	list_for_each_entry(buf, &hwc->buffers, head)
> +	list_for_each_entry_safe(buf, n, &hwc->buffers, head)
>  		iio_buffer_put(&buf->buffer);

This looks like an unrelated fix.  Push back into the
original patch?

>  	kfree(hwc);
>  }
>  EXPORT_SYMBOL_GPL(iio_hw_consumer_free);
>  
> +static void devm_iio_hw_consumer_release(struct device *dev, void *res)
> +{
> +	iio_hw_consumer_free(*(struct iio_hw_consumer **)res);
> +}
> +
> +static int devm_iio_hw_consumer_match(struct device *dev, void *res, void *data)
> +{
> +	struct iio_hw_consumer **r = res;
> +
> +	if (!r || !*r) {
> +		WARN_ON(!r || !*r);
> +		return 0;
> +	}
> +	return *r == data;
> +}
> +
> +/**
> + * devm_iio_hw_consumer_alloc - Resource-managed iio_hw_consumer_alloc()
> + * @dev: Pointer to consumer device.
> + *
> + * Managed iio_hw_consumer_alloc. iio_hw_consumer allocated with this function
> + * is automatically freed on driver detach.
> + *
> + * If an iio_hw_consumer allocated with this function needs to be freed
> + * separately, devm_iio_hw_consumer_free() must be used.
> + *
> + * returns pointer to allocated iio_hw_consumer on success, NULL on failure.
> + */
> +struct iio_hw_consumer *devm_iio_hw_consumer_alloc(struct device *dev)
> +{
> +	struct iio_hw_consumer **ptr, *iio_hwc;
> +
> +	ptr = devres_alloc(devm_iio_hw_consumer_release, sizeof(*ptr),
> +			   GFP_KERNEL);
> +	if (!ptr)
> +		return NULL;
> +
> +	iio_hwc = iio_hw_consumer_alloc(dev);
> +	if (IS_ERR(iio_hwc)) {
> +		devres_free(ptr);
> +	} else {
> +		*ptr = iio_hwc;
> +		devres_add(dev, ptr);
> +	}
> +
> +	return iio_hwc;
> +}
> +EXPORT_SYMBOL_GPL(devm_iio_hw_consumer_alloc);
> +
> +/**
> + * devm_iio_hw_consumer_free - Resource-managed iio_hw_consumer_free()
> + * @dev: Pointer to consumer device.
> + * @hwc: iio_hw_consumer to free.
> + *
> + * Free iio_hw_consumer allocated with devm_iio_hw_consumer_alloc().
> + */
> +void devm_iio_hw_consumer_free(struct device *dev, struct iio_hw_consumer *hwc)
> +{
> +	int rc;
> +
> +	rc = devres_release(dev, devm_iio_hw_consumer_release,
> +			    devm_iio_hw_consumer_match, hwc);
> +	WARN_ON(rc);
> +}
> +EXPORT_SYMBOL_GPL(devm_iio_hw_consumer_free);
> +
>  /**
>   * iio_hw_consumer_enable() - Enable IIO hardware consumer
>   * @hwc: iio_hw_consumer to enable.
> diff --git a/include/linux/iio/hw-consumer.h b/include/linux/iio/hw-consumer.h
> index f16791b..90ecfce 100644
> --- a/include/linux/iio/hw-consumer.h
> +++ b/include/linux/iio/hw-consumer.h
> @@ -14,6 +14,8 @@ struct iio_hw_consumer;
>  
>  struct iio_hw_consumer *iio_hw_consumer_alloc(struct device *dev);
>  void iio_hw_consumer_free(struct iio_hw_consumer *hwc);
> +struct iio_hw_consumer *devm_iio_hw_consumer_alloc(struct device *dev);
> +void devm_iio_hw_consumer_free(struct device *dev, struct iio_hw_consumer *hwc);
>  int iio_hw_consumer_enable(struct iio_hw_consumer *hwc);
>  void iio_hw_consumer_disable(struct iio_hw_consumer *hwc);
>